Carbocyanine dye



Patented Dec. 24, 1940 UNITED STATES 2,226,156 CARBOCYANINE DYE Leslie ,G. S. Brooker and Robert H. Sprague Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N

New Jersey No Drawing.-

rial No. 320,164. 1939 12 Claims.

acid, with cyclammonium quaternary, salts containing an alkylmercapto group in the 02- or position.

We have now found that anhydride's of certain dibasic carboxylic acids can be condensed with cyclammonium quaternary salts. containing a methyl group in the (ll-position, to give carbocyanine dyes quite different from the carbocyanine dyes obtainable by the prior methods. Our new carbocyanine dyes are characterized by having an organic group on the trimethine chain attached to which is a carboxyl group. This carboxyl group can be esterified with alcohols to give the corresponding esters Some of our new dyes sensitize photographic silver halide emulsions. Our new dyes can be employed to dye textiles, and as the light absorbing means in the manufacture of light filters.

It is, accordingly, an object of our invention to provide new carbocyanine dyes. A further object is to provide a process for preparing carbocyanine dyes. Other-objects willbecome apparent hereinafteh r In accordance with our invention, we condense a phthalic anhydride (1. e., an anhydride of a 'benzene-1,2-dicarboxylic acid) or succinic anhydride with acyclammonium quaternary salt containing a methyl group in the wposiltion, in the presence of abasic condensingagent. ,2- methylbenzothiazole, 2-methylbenzoselenazole,' 2- methylbenzoxazole, 2-methylthiazoline, -methylnaphthothiazole and -methylnaphthoxaz ole quaternary salts condense readily with'these anhydrides. As basic condensing agents, we have found that pyridine and pyridine containing a strong organic base are advantageously employed. strong organic base, we mean an organic having a dissociation constant substantially greater than that of pyridine. Typical strong organic bases are, of course, triethylamine, piperidine and triethanolamine. Heat accelerates the formation of ournew dyes. The carboxylated dyes obtained in the foregoing manner can be esterified with alcohols in the presence of Application February 2 1, 1940, Se-

In Great Britain March 30,

' wherein R. and R each represent an alkyl group, 10

PATENT omes acid esterification catalysts, such as hydrogen chloride.

Our dyes can be represented bythe following general formula:

such as methyl, ethyl, isoamyl, 'benzyl or cethoxyethyl for example, R" represent-s a mem-' ber selected from the group consisting of hydrogen and alcohol'radicals, i. e.,.alkyl groups, Q

represents a member selected from the group consisting of o-phenylene and ethylene group-s, X represents an acid radical such as p-toluenesulfonate, iodide, chloride, bromide, or perchlorate for example, and Z represents the nonmetallic atoms necessary to completev a heterocyclic organic nucleus,'such as a benzothiazole nucleus .(e. g., 5-chlorobenzothiazole), a benzoselenazole nucleus, a naphthoxazole nucleus, a naphthothiazole nucleus or a thiazoline nucleus for example. j The following examples will serve to demonstrate the manner of obtaining our new dyes. These examples, however, are not intended to limit our invention: EXAMPLE 1. 3,3-diethyZ-9- (o-carboxyphe'nyl) 4,5,4,5-dibenzothiacarbocyanine-p-toluenesulfonate excess) of phthalic anhydride were mixed together inl5 cc. of pyridine. The resulting mixture was boiled, under reflux, for ten minutes.

Green crystals of the dye separated slowly from the boiling mixture. to 0 (3., the dye filt red off, washed on the filter with acetone and water and finally dried in the air. 0.35 g. (18% yield) of dye were obtained.

'It was recrystallized from methyl alcohol (100 cc. per gram of dye) and obtained as green crystals, melting at 216 to 218 0., with decomposition. 0.3 g. (16% yield) of the pure dye was melting at 280 to 282 0., with decomposition, This yellow product was identified as 2- (l-methyl-Z (1) -fi-naphthothiazolylidene) 1,3-indanedione, which has the following formula:

, (3H3 I g EXAMPLE 2.3,3' diethyl- 9- (o-carboxypheny l) thiacarbocyanine iodide 1.5 g. (2 mol.) of 2-methylbenzothiazole ethiodide and 3.0 g. (1 mol.+700% excess) of phthalic EXAMPLE 3.3,3'diethyl- 7 (o-ca boxyphenyl) thiaeolinooarbocyanine iodide red crystals having a metallic reflex and melting, with decomposition, at 250 to 252 C. A methyl alcoholic solution of the dye showed an absorption maximum at about 4-60 mu. The dye had practically no sensitizing action on photographic silver halide emulsions.

EXAMPLE 4.3,3-diethyl- 9 -(o-carbocryphenyl) selenacarbocyanine iodide reflux, for ten minutes. The resulting purple solution was cooled, diluted with 100 cc. of diethyl ether and chilled to 0 C. The dye which and melting at 214 to 215 C. with decomposition. A methyl alcoholic solution of the dye showed an absorption maximum at 575 mu. The dye sensitized a gelatino-silver-bromiodide emulsion moderately out to 645 mu. with a maximum at 600 mu.

EXAMPLE 5.3,3-dimethyl-9-(o-carbOxz/pheng Z) -oxacarbocyanine iodide ing material, since on recrystallization from methyl alcohol (30 cc.), only 0.3 g. (11% yield) of violet crystals, melting at 234 to 236 C1, With maximum at about 490 mu. a gelatino-silver-bromiodide about 560 mu. with a maximum at 530 mu.

EXAMPLE 6. 5,5diohloro-3,3'-diethyl-9-(ocarboxyphenyl) -thiacarbocyanine iodide 3.8 g. (2 mol.) of 2-methy1-5-ch1orobenzothiazole etho p toluenesulfonate an absorption maximum at about 565 mu. The dye sensitized a gelatino-silver-bromiodide fairly a maximum at EXAMPLE 7 .-9- (gearbox-116mm"). my

thiacarbocyanmg c 6.1 g. (2 mol.) of Z-methylbenzothiazole ethiodide and 8.0 g. (.1 m01.+?00% excess) of succinic anhydride were mixed together'in 30 cc. of'pyridine. The mixture was boiled, under reflux, for fifteen minutes. The resulting. purple solution was cooled and diluted with diethyl ether to precipitate the dye. The precipitated dye was dissolved in 50 cc. of methyl alcohol; The methyl alcoholic solution was treated with an excess of sodium perchlorate dissolved in methyl alcohol to precipitate the dye as the perchlorate. 0.7 g. (13% yield) of green crystals were thus obtained. The dye was recrystallized from methyl alcohol (50 co. per gram of dye) and obtained, in 11% yield, as minute green crystals-melting with decomposition at 211to 213 C. 'A methyl alcoholic solution of the dye showed an absorption maximum at 550 mu. The dye sensitized a gelatino-silver-bromiodide emulsion out to 640 mu., with maxima at 600 mu. and 5&0 mu.

EXAMPLE 8.--3,3'-diethyl 9-(o-carbethoxyphem Z) -4,5,4,5 -dz'benz0thiaca.rb0cyanine bromide 2.0 g. 1 mol.) of 3,3'-diethy l-9-(o-carboxyphenyl) -4,5,4,5-dibenzothiacarbocyanine-p tol uenesulfonate were dissolved in 300 cc. of; a bsolute ethyl alcohol and a stream-of dry hydrogen chloride was passed in the solution for three hours. The solution was then concentrated to a volume of 200 cc. An excess of potassium..bromide was then added to the solution, the solution diluted with cc. of diethyletherrand chilled to 0 C. The dye which separated was filteriedofi,v washed with acetone and water andfinally dried in the air. 1.4 g. (77%yield) of green crystals were thus obtained. .These were recrystallizedfrom'me'thyl alcohol (66 cc. per gram ioiJdye) and obtained, in 50% yield, as bright green crystals melting with decomposition. at 245. to .247" C. A methyl alcoholic solution of the dye showed an absorption maximum at 598 mu. The dye sensitized a gelatino-silver-bromide emulsion less strongly than the corresponding carboxy dye (see Example 1) out to 705 mu., with a maximum at ExAi/iPLE 9.--9-(o carbmet'hoxyphenyl) -3,3'd,z"-

ethyl 4,5,4',5' dibenzothiacarbocyanme bro mide 2.0 g. (1 mol.) of'3,3 -diethyl-9-(o-carboxyphenyl) 4,5,4,5- dibenzothiacarbocyanine bro midewere dissolved in cc. of absolute methyl alcohol. The solution was boiled, under reflux, while-dry hydrogen'chloride was passed into the solution for three hours. 1 At the end of this time, an excess of potassium bromide was added to the hot solution and the resulting mixture was chilled to .0?" C. Theldye which rseparated. was filtered off; washed i with water' an'dacetone and finally obtained. fIt was recrystallized from methyl alcohol filfifr ccfp'er gram of dye) andobtained as minuteg reen'crystals having a: metallic reflex Ext-tats 10.-:-Bi's-3: methyl-'1 nemia-1011mm .lo'ne- 4) ic-carborcyphenyl) -methinomonol 1215,5132 11 1 1 10f 3 methy1'-l-phenyl-5-pyra excess) of phthalic.

anhydride were mixed together in 15 cc. of pyridine. The mixture was boiled, under reflux, for ten minutes. The orange-red solution was diluted to 1200 cc. with water, a small amount of colorless solid filtered off and the filtrate made acid with acetic acid. was filtered off, washed with water and dried in the air. Yield of crude orange dye was 1.5 g., 63%. After recrystallization from methyl alcohol, (45 cc./g.), the product was obtained as red crystals melting, with decomposition at 217 to 218 C. Yield ".7 g., 29%. at 4940 A. in methyl alcohol; sensitizing action.

- As shown in the aboveexamples, an excess of the anhydrid-eis advantageously employed. Excesses of from 100 to '700%- are advantageously employed.

In the preparation of photographic emulsions containing our new dyes, it is only necessary to disperse the dyes throughout the emulsions. The methods of incorporating the dyes in emulsions The dye had no are simple and-well known to those skilled in the art.

It is convenient to add the dyes from solutions in appropriate solvents. Methanol has proven satisfactory as a solvent for our new dyes. Ethyl alcohol or acetone may also be employed. Ordinarily", it is advantageous to incorporate our newfdyesj in the finished, washedemulsions'. The dyes should, of course, be'uniform ly distributed throughout the emulsions.

f The concentration. of-our new dyes in the emulsion canvary widely,i'. eirom about 5 to about 100 mg.per literoiflowable emulsion. ,The concentrationofthe dye will vary according to the type of light-sensitive material in the emulsion and according to the effects desired. The suit- The orange precipitate Absorption maximum able and most economical concentration for any given emulsion will be apparent to those skilled in the art upon making the ordinary tests and observations customarily used in the art of emulsion making.

To prepare a gelatino-silver-halide emulsion, sensitized with our new dyes, the following procedure is satisfactory: A quantity of the dye desired is dissolved in methyl alcohol or other suitable solvent and a volume of this solution (which may be diluted with water) containing from to 100 mg. of the dye is slowly added to about 1000 .cc. of a developing-out gelatino-silver-halide emulsion with stirring. Stirring is continued until the dye is uniformly distributed throughout the emulsion. With most of our new dyes, to mg. of dye, per liter of emulsion sumces to produce the maximum sensitizing eifect with the ordinary gelatino-silver-bromide (including bromiodide) emulsions. With fine-grain emulsions, which includes most of the ordinarily employed ,gelatino silver chloride emulsions, somewhat larger concentrations of dye may be necessary to secure the optimum sensitizing effect.

The above statements are only illustrative and not to be understood as limiting our invention in any sense, as it will be apparent that our dyes can be incorporated by other methods in many of the photographic emulsions customarily employed in the art, such, for instance, as by bathing a plate or film upon which the emulsion has been coated in a solution of the dye in an appropriate solvent. The bathing methods, however, are not to be preferred ordinarily.

What we claim as our invention and desire to be secured by Letters Patent of the United States is:

1. A carbocyanine dye characterized by the following general formula:

wherein R and R each represent an alkyl group, R" represents a member selected from the group consisting of hydrogen and alkyl groups, Q represents a member selected from the group consisting of o-phenylene and ethylene groups, X represents an acid radical and Z represents the non-metallic atoms necessary to complete a heterocyclic organic nucleus.

2. A carbocyanine dye characterized by the following general formula:

wherein R and R' each represent an alkyl group, R" represents a member selected from the group consisting of hydrogen and alkyl groups, Q represents a member selected from the group consisting of o-phenylene and ethylene groups, X represents an acid radical and Z represents the non-metallic atoms necessary to complete a heterocyclic organic nucleus selected from the group consisting of benzothiazole, benzoxazole, benzoselenazole, naphthothiazole, naphthoxazole and thiazoline nuclei.

3. A carbocyanine dye characterized by the following general formula:

wherein R and R each represent an alkyl group and X represents an acid radical.

4. A carbocyanine dye characterized by the fol 1 lowing general formula:

wherein R and R each represent an alkyl group and X represents an acid radical.

6. A 3,3'-diethyl-9- (o-carboxyphenyl) -4,5,4',5'- dibenzothiacarbocyanine salt.

7. A 3,3'- diethyl 9 -(o-carboxyphenyl) thiacarbocyanine salt.

8. A 3,3'-diethyl-9-(o-carboxyphenyl)- selenacarbocyanine sal 9. A process for preparing a carbocyanine dye comprising condensing, in thepresence of a basic condensing agent, an organic acid anhydride selected from the group consisting of phthalic anhydrides and succinic anhydrides, with a cyclammonium quaternary salt containing a methyl group in the a-position.

10. A process for preparing a carbocyanine dye comprising condensing, in the presence of pyridine, an organic acid anhydride selected from the group consisting of phthalic anhydrides and succinic anhydrides, with a cyclammonium quaternary salt containing a methyl group in the ocposition. 1

11. A process for preparing a carbocyanine dye comprising condensing, in the presence of pyridine, phthalic anhydride with a cyclammonium quaternary salt containing a reactive methyl group in the a-position.

12. A process for preparing a carbocyanine dye comprising condensing, in the presence of pyridine, phthalic anhydride with a cyclammonium quaternary salt selected from the group consisting of 2-methylbenzothiazole, 2-methylbenzoxazole, 2-methylbenzo selenazole, -methylnaphthothiazole, ,u-methylnaphthoxazole and 2-methylthiazoline quaternary salts.

LESLIE G. S. BROOKER. ROBERT H. SPRAGUE.

CERTIFICATE OF CORRECTION. Patent No. 2,226,15 6. December 211., 1914.0. LESLIEG. s. BROOKER, ET AL. v It is hereby certified that error appears in the printed specification of the ibove numbered patent requiring correction as follows: Page 2, sec 0nd column, line 71, for "207" read "207 C. A methyl alcoholic solution of the dye showed-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the P'atent Office.

Signed and sealed this 25th day of February, A. D. 19111. 5 E

I Henry Van Arsdale, 3 Acting Commissioner of Patents, 

